Battery connections for battery start of internal combustion engines

ABSTRACT

A battery pack for use in providing starting power for a starter motor of an internal combustion engine and to supply power to one or more auxiliary loads. The battery pack includes an outer housing that encloses a plurality of battery cells. A control unit is positioned within the outer housing and is connected to at least a starter switching element and an auxiliary switching element. The control unit controls the position of both the starter switching element and the auxiliary switching element to selectively connect the battery cells to the starter motor and the auxiliary loads. The battery pack further includes an ignition input terminal that is connected to the ignition circuit of the internal combustion engine such that the control unit can monitor the operational status of the internal combustion engine. The control unit can selectively ground the ignition coil of the ignition circuit to enable and/or terminate operation of the internal combustion engine.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based on and claims priority to U.S.Provisional Patent Application Ser. No. 62/568,853, filed Oct. 6, 2017,the disclosure of which is incorporated herein by reference.

BACKGROUND

The present disclosure relates to a lithium ion battery pack havingbattery terminals designed for use in a starting circuit for an internalcombustion engine of outdoor power equipment, such as a lawn tractor.More specifically, the present disclosure relates to a battery pack thatincludes specifically designed terminals and an internal control unit todirect power from the battery pack to systems of the outdoor powerequipment both before and after starting of the internal combustionengine.

Presently, many different types of outdoor power equipment includeelectronic starting circuits that allow the user to start the internalcombustion engine of the outdoor power equipment through either a keyswitch or a push button. Most of these starting systems include a leadacid battery that provides the voltage and current required foractivating the starting system of the outdoor power equipment. In manycases, the lead acid battery is a 12-volt battery that is rechargedduring operation of the outdoor power equipment.

Although lead acid batteries have been used for a very long time and arerelatively inexpensive, if the voltage stored by the lead acid batteryis completely depleted, the lead acid battery may become ineffective atstoring a charge and would thus need to be replaced. Since many piecesof outdoor power equipment can sit idle for extended periods of time, ifthe lead acid battery is not removed and kept charged, the lead acidbattery can become completely discharged and thus must be replaced. Incases of newly purchased equipment, this replacement may fall under themanufacturer's warranty and would need to be replaced by themanufacturer.

SUMMARY

The present disclosure relates to a starter battery pack for use with apiece of outdoor power equipment, such as but not limited to a lawntractor. More specifically, the starter battery pack includes an outerhousing that encloses a plurality of individual battery cells. Thestarter battery pack includes a series of terminals that can beconnected to components within the equipment or device powered by thebattery pack.

In one embodiment, the battery pack includes a starter switching elementthat is positioned within the outer housing between a starter terminaland the battery pack. The starter terminal, in turn, is connected to astarter motor for the internal combustion engine. The control unit ofthe battery pack controls the condition of the starter switching elementto power the starter motor as desired.

The battery pack further includes an auxiliary switching element that ispositioned within the outer housing between an auxiliary terminal andthe battery cells. The control unit can control the condition of theauxiliary element to selectively connect the battery cells to one ormore auxiliary loads.

The battery pack further includes an ignition input terminal that isconfigured to be connected to an ignition circuit of the internalcombustion engine. The control unit includes an RPM input pin that isconnected to the ignition input terminal such that the control unit candetect the operational status of the internal combustion engine.

In one embodiment of the present disclosure, the battery pack includes ashutdown switching element. The control unit can control the conditionof the shutdown switching element to selectively connect an ignitioncircuit of the internal combustion engine to ground. Connecting theignition circuit to ground either inhibits operation of the internalcombustion engine or, when the internal combustion engine is operating,terminates operation of the internal combustion engine. In this manner,the control unit of the battery pack can selectively enable or terminateoperation of the internal combustion engine through an internal shutdownswitching element.

Various other features, objects and advantages of the invention will bemade apparent from the following description taken together with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the best mode presently contemplated of carryingout the disclosure. In the drawings:

FIG. 1 is a front perspective view of a lawn tractor including thebattery pack according to some embodiments;

FIG. 2 is a series of perspective views of the battery pack according tosome embodiments;

FIG. 3 is a front perspective view of the battery pack according to someembodiments;

FIG. 4 is an electrical schematic illustration of the operatingcomponents of the starter battery pack according to some embodiments;

FIG. 5A is a schematic illustration of the operating condition of theswitching elements when the internal combustion engine is off;

FIG. 5B is a schematic illustration of the operating condition of theswitching elements when the internal combustion engine is running;

FIG. 5C is a schematic illustration of the operating condition of theswitching elements during cranking of the starter motor;

FIG. 6 is an electrical schematic illustration showing high-sideswitching according to some embodiments;

FIG. 7 is an electrical schematic illustration showing low-sideswitching according to some embodiments;

FIG. 8 is an electrical schematic illustration of an alternateembodiment of the battery pack including two enable inputs according tosome embodiments;

FIG. 9 is an electrical schematic illustration of the operatingcomponents of the starter battery pack including two enables accordingto some embodiments

FIG. 10 is an electrical schematic illustration of the operatingcomponents of the starter battery pack including two enables accordingto some embodiments;

FIG. 11A is a schematic illustration of the operating condition of theswitching elements in a two enable system when the internal combustionengine is off according to some embodiments;

FIG. 11B is a schematic illustration of the operating condition of theswitching elements in a two enable system when the internal combustionengine is running according to some embodiments; and

FIG. 11C is a schematic illustration of the operating condition of theswitching elements in a two enable system during cranking of the startermotor according to some embodiments.

DETAILED DESCRIPTION

The present disclosure is directed to a battery pack and starting systemfor an internal combustion engine of a lawn tractor. The drawing figuresdepict the use of the battery pack and starting system with a lawntractor. However, it should be understood that the battery pack andstarting system could be utilized with other types of outdoor powerequipment such as with lawn mowers, riding tractors, snow throwers,pressure washers, tillers, log splitters, zero-turn radius mowers,walk-behind mowers, riding mowers, stand-on mowers, pavement surfacepreparation devices, industrial vehicles such as forklifts, utilityvehicles, commercial turf equipment such as blowers, vacuums, debrisloaders, overseeders, power rakes, aerators, sod cutters, brush mowers,sprayers, spreaders, etc.

FIG. 1 illustrates a riding lawn tractor 10 that includes a mowingassembly 11 mounted beneath a vehicle chassis 12 supported by fourwheels 14. The lawn tractor 10 includes an internal combustion engine(not shown) that powers both the rear drive wheels and the mower bladecontained within the mowing assembly 11. A steering wheel 16 allows anoperator positioned in the seat 18 to control the movement of the lawntractor 10, as is conventional. In the embodiment shown in FIG. 1, thelawn tractor 10 includes an ignition switch 19 that is used by theoperator to start operation of the internal combustion engine. Theignition switch 19 could be a three position key switch or could be apush-button. The operation of the ignition switch 19 will be detailedbelow. The details of the lawn tractor 10 shown in FIG. 1 are meant ofillustrative purposes only, since the lawn tractor 10 could have variousdifferent operator controls and physical configurations while fallingwithin the scope of the present disclosure.

FIG. 2 illustrates one possible embodiment of a battery pack 40constructed in accordance with the present disclosure. The battery pack40 includes a two-piece outer battery housing 22 that includes a bottomportion 24 and a top portion 26. The top portion 26 includes a powerlevel display 28 that includes a plurality of individual indicatorlights 30. Although the embodiment shown in FIG. 2 includes multipleindicator lights 30, it is contemplated that the multiple indicatorlights 30 could be replaced by a single LED that changes color dependingupon the charge stored on the internal battery cell. As an example, theindicator lights 30 could be replaced by a single LED that changes colorfrom green to yellow to red, depending upon the state of charge on theinternal battery pack. Alternatively, the multiple indicator lights 30could be replaced by a single LED that flashes, remains on in a steadystate, or is turned off depending upon the charge level of the batterypack 40. Such embodiment would allow for a single color LED.

In the embodiment shown in FIG. 2, the battery pack 40 includes sixindividual battery cells 34 that are organized and connected to eachother and are contained within the outer battery housing 22, as will bedescribed in greater detail below. In the embodiment shown in FIG. 2,the six individual battery cells 34 are stacked in two rows eachincluding three cells. However, it is contemplated that otherconfigurations could be utilized while operating within the scope of thepresent disclosure. The size of the outer battery housing 22 isconfigured to accommodate the six battery cells 34, which provides foradditional interior space for the charging circuit and switching circuitto be described below.

FIG. 3 illustrates the circuit board 36 that includes the indicatorlights 30. In addition, the circuit board 36 includes an activationswitch 38 that allows the user to test the charge of the battery pack32. For example, the indicator lights 30 may only provide an indicationto the user of the charge of the battery pack 32 when the activationswitch 38 is actuated by the user.

In the embodiment illustrated, each of the individual battery cells 34of the battery pack 40 can be one of two different types of storagecells. In one embodiment, each of the cells 34 is a common lithium ionbattery, referred to as an NMC (nickel magnesium cobalt) battery. TheNMC battery cells may be configured to have a pre-defined voltage level.For example, each of the NMC battery cells in battery pack 34 may have arating of 3.6 volts. In other embodiments, each of the battery cells 34may be another type of lithium ion battery referred to as a lithium ironphosphate cell (LiFePO4, LFP). A lithium iron phosphate (“LFP”) batteryis a type of lithium ion rechargeable battery that is typically used forhigh power applications. An LFP battery allows for reduced protectioncircuitry as compared to an NMC battery, and typically offers a longerusable life, better power density and is inherently safer. An LFPbattery has a typical maximum charge capacity of 3.2 volts each in theembodiment shown in FIG. 3. In the present disclosure, both the LFP andNMC battery cells will be referred to as lithium ion battery cells. Inaddition, other chemistries are contemplated as being useful for thebattery cells 34.

In the embodiment illustrated, the six individual battery cells 34 ofthe battery pack 40 are believed to be able to provide enough current tostart an internal combustion engine of the lawn tractor many times,which means that there will be a relative significant amount of timebetween charges.

FIG. 4 illustrates the operating configuration of a battery pack 40according to some embodiments. The battery pack 40 is shown in FIG. 4 asincluding a series of individual battery cells 34 connected in series.However, it should be understood that a different number of batterycells 34 could be utilized and that the battery cells could be connectedin series, parallel or series-parallel configurations depending upon theoutput requirements from the combination of the battery cells 34. Thebattery pack 40 includes a control unit 42 within an outer housing 44schematically shown in FIG. 4. The control unit 42 is positioned toreceive inputs from other systems associated with the operation of theinternal combustion engine and to control operation of multiple switchesas will be described in greater detail below. In the embodiment shown inFIG. 4, the starter switching element 66 is shown positioned between thepositive terminal of the group of battery cells 34 and the starter motor64. In this manner, the starter switching element 66 can replace thestarter solenoid.

As illustrated in FIG. 4, the battery pack 40 includes an ignition inputterminal 46 that is connected to the ignition circuit 48, including anignition coil, from the internal combustion engine. An ignition signalreceived at the ignition input terminal 46 is fed into the RPM input pin50 of the control unit 42. The ignition signal from the ignition circuit48 will include a series of pulses that correspond to the rotationalspeed of the internal combustion engine. By monitoring the pulsespresent at the RPM input pin 50, the control unit 42 will be able todetermine whether the internal combustion engine is running or whetherthe internal combustion engine is not running.

In the embodiment shown in FIG. 4, the control unit 42 includes anignition shutdown pin 52 connected to a shutdown switching element 54.The shutdown switching element 54 is connected between the ignition coilof the ignition circuit 48 of the internal combustion engine and ground56. When the shutdown switching element 54 is in the closed condition,the ignition circuit 48 is connected directly to ground 56 which willground the ignition coil. Grounding the ignition coil will eitherterminate operation of the internal combustion engine or will preventstarting of the internal combustion engine. When the shutdown switchingelement 54 transitions to the open condition shown in FIG. 4, theignition circuit 48 would be ungrounded and thus allow for operation orstarting of the internal combustion engine. In the embodiment shown inFIG. 4, the shutdown switching element 54 is a MOSFET switch that cantransition between “open” and “closed” conditions through theapplication of a voltage to the MOSFET from the control unit 42 (e.g.via ignition shutdown pin 52). Although a MOSFET is described in oneembodiment as the shutdown switching element 54, it should be understoodthat different types of switching elements, such as an SCR, transistor,IGBT or a relay, could be utilized while operating within the scope ofthe present disclosure.

The battery pack 40 includes an enable terminal 58 that is connected toan ignition switch 19. The ignition switch 19 can be one of multipledifferent types, such as a multi-position key switch, a push buttonstarter or any other type of device or switch that can generate anenable signal along line 60. As an illustrative example, when theignition switch 19 is a multi-position key switch, when the key switchis moved to a cranking position to start the engine, a ground signal ispresent along the line 60, which in turn is received at the enable inputpin 62 of the control unit 42. Likewise, when the ignition switch 19 isa push button, depressing the push button creates a similar groundsignal along line 60, which is also received at the enable input pin 62.

When the control unit 42 receives the enable signal at the enable inputpin 62, the control unit 42 can then determine whether starting of theinternal combustion engine should be allowed to occur. For example, ifthe control unit 42 determines that the internal combustion engine isrunning, a starting action is not necessary, and could damage thestarter motor 64 or the internal combustion engine itself. If thecontrol unit 42 determines that the internal combustion engine is notrunning, based upon the signal present at the RPM input pin 50, thecontrol unit 42 can initiate operation of the starter motor 64. To doso, the control unit 42 controls the operational state of a starterswitching element 66 which is positioned between the series of batterycells 34 and the starter motor 64. When the starter switching element 66is in the closed condition, the voltage from the series of battery cells34 is present at the 12 volt starter terminal 68 of the battery pack 40.The 12 volt starter terminal 68 is connected directly to the startermotor 64 to provide the required twelve volts needed to operate thestarter motor. In the embodiment shown in FIG. 4, the starter switchingelement 66 is a MOSFET switching element, the condition of which can becontrolled by the control unit through the voltage present at thestarter control pin 70. Although a MOSFET is described in one embodimentas the starter switching element 66, it should be understood thatdifferent types of switching elements, such as an SCR, transistor, IGBTor a relay, could be utilized while operating within the scope of thepresent disclosure.

After the starter switching element 66 is moved to the “closed”condition, the battery voltage is supplied to the starter motor 64through the starter terminal 68. The control unit 42 monitors thesignals from the ignition circuit 48 through the RPM input pin 50 todetermine whether the internal combustion engine starts. Once thecontrol unit 42 determines that the internal combustion engine hasstarted, the control unit 42 moves the starter switching element 66 backto the “open” condition to remove the voltage from the battery cells 34from the starter motor 64. The control unit 42 can disable the startermotor voltage by keeping the starter switching element 66 “open” if theignition switch signal 19 is released before the engine is detected asrunning. This decision is based on whether the control unit 42 isprogrammed to crank only while the ignition switch signal 19 is presentor whether the control unit 42 goes into an auto crank mode where thestarting process continues regardless of whether the ignition switchsignal 19 remains present.

In addition to providing voltage from the series of battery cells 34 tothe starter motor 64 to initiate operation of the starter motor, thecontrol unit 42 can control the condition of an auxiliary switchingelement 72 which is connected between the series of battery cells 34 andan auxiliary terminal 74. The auxiliary terminal 74 provides power to aseries of auxiliary devices and loads 76 of the lawn tractor though anauxiliary bus. These auxiliary loads can include lights, radio, adisplay, gauges or any other component on the vehicle that could bepowered when the internal combustion engine of the tractor is notoperating. As an illustrative example, if the operator of the lawntractor wishes to operate the radio or lights of the tractor withoutturning the tractor on, the operator could move the key switch to anauxiliary position, which would be sensed by the control unit 42 at theenable input pin 62. Since the internal combustion engine is notrunning, the control unit 42 would make this determination based uponthe signal present at the RPM input pin 50. Based upon these two inputs,the control unit 42 can generate a signal on the auxiliary pin 71 whichwill then transition the auxiliary switching element 72 to the “closed”condition and supply battery power to the auxiliary loads 76 for alimited period of time.

As can be understood by the above description, the inclusion of theignition input terminal 46 on the battery pack 40 allows the controlunit 42 to monitor the operation of the internal combustion engine. Insuch a manner, the control unit 42 is able to detect whether theinternal combustion engine is running and allows the control unit 42 todisconnect the series of battery cells 34 from the auxiliary devicesusing the auxiliary switching element 72 after the user has stoppedoperation of the internal combustion engine. This feature would preventthe battery pack 40 from draining the battery cells 34 if the ignitionswitch 19 is left in the on position for an extended period of timeafter the engine has stopped operation. In some embodiments, the controlunit 42 uses elapsed time from termination of the engine operation todisconnect the battery pack 40 from the auxiliary devices. In addition,the control unit 42 will be able to ground the ignition circuit 48 ofthe internal combustion engine if desired.

The inclusion of the ignition input terminal 46 on the battery pack 40also allows the ignition switch 19 to provide additional functions whenthe ignition switch 19 is a momentary push button. Specifically, whenthe internal combustion engine is running, the user can again depressthe momentary push button to stop operation of the internal combustionengine. When the control unit 42 is sensing operation of the enginethrough the RPM input pin 50 and then receives a signal at the enableinput pin 62, the control unit 42 can stop the engine by grounding theignition circuit 48 through the shutdown switching element 54. As statedabove, when the shutdown switching element 54 is in its “closed”condition, the ignition circuit 48 of the internal combustion engine isgrounded, which stops operation of the internal combustion engine.Examples of use of this feature could be utilized in a pressure washerin which the internal combustion engine includes a spray wand having atrigger switch. When the trigger switch is initially pulled, the triggerswitch will function in the same manner as a push button startingswitch. Upon detecting the trigger switch, the microcontroller wouldstart the internal combustion engine. When the trigger switch isreleased, the control unit 42 would sense such change of state andterminate operation of the internal combustion engine through theshutdown switching element 54. In some embodiments, the control unit 42may include a time delay circuit to prevent shutdown of the internalcombustion engine immediately upon the user releasing the triggerswitch. In one example, the time delay circuit may provide a ten secondtime delay. However, other time delay values of more than ten seconds orless than ten seconds are also contemplated. Other possible uses arealso contemplated as being within the scope of the present disclosure.

FIGS. 5A-5C illustrate the three different operating conditions and theposition of the various switching elements contained within the batterypack 40. In FIG. 5A, the internal combustion engine is in an offcondition. In this state, the shutdown switching element 54 is in a“closed” condition such that the ignition circuit 48 is connected toground 56. In the engine off condition, the battery cells are notconnected to either the auxiliary loads 76 or the starter motor 64 bythe starter switching element 66 and the auxiliary switching element 72being in the “open” condition.

If the user desires to begin operation of the internal combustionengine, which is indicated by movement of the ignition switch, thecontrol unit causes the shutdown switching element 54 to transition intothe open condition. In this condition, the ignition circuit 48 isdisconnected from the ground 56. At the same time, both the starterswitching element 66 and the auxiliary switching element 72 transitionto the closed condition such that the battery cells 34 are connected toboth the auxiliary loads 76 and the starter motor 64, as shown in FIG.5C.

Once the internal combustion engine begins running, which the controlunit senses through the RPM input pin, the control unit causes thestarter switching element 66 to transition into the open condition,thereby disconnecting the battery cells 34 from the starter motor 64,while maintaining the auxiliary switching element in a closed condition,as shown in FIG. 5B. As can be understood in FIGS. 5A-5C, the controlunit contained within the battery pack 40 can start the internalcombustion engine, control the battery power connections to theauxiliary loads and terminate operation of the internal combustionengine.

FIG. 6 provides a more detailed illustration of the operation of thestarter switching element 66. As illustrated, the starter switchingelement 66 is positioned at the positive terminal of the group ofbattery cells 34. The ignition switch 19 is positioned between thestarter switching element 66 and the starter motor 64. When the ignitionswitch 19 is closed, the control unit 42 can detect the battery groundthrough the starter 64 via the shown diode/resistor circuit 83. Thecontrol unit 42 can then close the starter switching element 66, sendingcurrent through the starter motor 64. Thus, both the starter switchingelement 66 and the ignition switch 19 are required to be in the closedcondition for the voltage from the group of battery cells 34 to beprovided to the starter motor 64. The control unit 42 includes a sensingpin 78 that can sense the flow of current through the starter motor 64in the path to ground through the sensing resistor 80. Thus, when thestarter switching element 66 and ignition switch 19 are in their“closed” condition, current flows through the starter motor 64, which isthen sensed by the control unit 42 at the sensing pin 78. Once thecontrol unit 42 senses operation of the internal combustion engine inthe manner described previously, the control unit 42 causes thetransition of the starter switching element 66 back to the opencondition. When in the open condition, the starter motor 64 stopsoperating, which is confirmed by the control unit 42 by the lack of anyvoltage at the sensing pin 78.

FIG. 7 is an alternate arrangement in which the starter switchingelement 66 is located between the negative terminal of the group ofbattery cells 34 and ground. Once again, when the ignition switch 19 isclosed, the control unit 42 can detect the battery cell voltage throughthe starter 64 and the resistor bridge 82. The control unit 42 then cancause the starter switching element 66 to transition into the closedcondition as long as the engine is not running, thus protecting thestarter motor pinion gear. The starter switching element 66 provides apath to ground for the starter 64, at which time current will flow fromthe battery cells 34 through the starter motor 64. This current issensed through resistor 80 and through the current sensing pin 78. Onceagain, the control unit 42 can transition the starter switching element66 between open and closed conditions based upon a desire to operate thestarter motor 64 and upon sensing operation of the internal combustionengine.

Referring now to FIG. 8, thereshown is an alternate arrangement for thebattery pack 40. In this arrangement, the control unit 42 includes twoenable inputs rather than the single enable input shown in FIG. 4. Aswith the embodiment shown in FIG. 4, the battery pack 40 includes anenable terminal 58 that is connected to the ignition switch 19. A secondenable terminal 84 is connected to the auxiliary bus 86, which includesthe connection between the battery cells 34 and the auxiliary loads 76.Thus, the signal on the enable terminal 84 is directly dependent uponwhether the battery cells 34 are connected to the auxiliary loads 76through the auxiliary switching element 72. The use of the second enableterminal 84 allows the control unit 42 to detect when the ignitionswitch 19 is in the run position and the internal combustion engine isnot operating. Such situation may occur when the user wishes to operatethe auxiliary loads 76 without turning on the internal combustionengine. If in the run position for too long without the engine running,the control unit 42 can transition the auxiliary switching element 72back to the open condition to disconnect the battery cells 34 from theauxiliary load 76.

FIG. 9 shows another embodiment for the battery pack 40. In thisembodiment, the battery pack 40 includes two enable inputs, 58 and 84,that come from a key switch or push button. On typical key startingcircuits, the starter signal from the control unit would pass through abrake switch and a blade switch. The starter motor, in such embodiment,would not engage unless the brake is on and the blades are turned off.The second enable shown in FIG. 9 can be used to see if the safetyrequirements are met before engaging the starter motor 64. For example,the 12 V power supply feeding the auxiliary loads 76 could be directedthrough the blade and brake switches to determine if the switches areclosed. If a signal is received at the auxiliary input pin 73, thecontrol unit 42 will know that it is safe to operate the starter motor64. In an embodiment with a momentary push button for starting, thefirst press of the button will wake up the battery and turn on theauxiliary power for the auxiliary loads 76. A second press of the buttonwill be sensed by the control unit 42 and if the required signal ispresent at pin 73, the starter motor 64 will be activated. Additionally,if the push button is depressed and held in the depressed positon, thecontrol unit 42 can turn on the auxiliary power and initiate cranking ofthe engine which the push button is depressed.

FIG. 10 provides yet another embodiment in which the push button 90 andthe key switch 92 each generate two separate inputs for the control unit42. The push button 90 includes both an input line 94 and a safetyenable 96 that are received at separate input pins to the control unit42. The key switch 92 has a similar input line 98 and auxiliary enableline 100 received at pins on the control unit 42. The control unit 42operates in a similar manner as discuss with reference to FIG. 9 todetermine whether to active the starter motor 64.

FIGS. 11A-11C illustrate the three different operating conditions andthe position of the various switching elements contained within thebattery pack 40 shown in FIGS. 9 and 10 with two enables. In FIG. 11A,the internal combustion engine is in an off condition. In this state,the shutdown switching element 54 is in a “closed” condition such thatthe ignition circuit 48 is connected to ground 56. In the engine offcondition, the battery cells are not connected to either the auxiliaryloads 76 or the starter motor 64 by the starter switching element 66 andthe auxiliary switching element 72 being in the “open” condition. Inthis condition, both of the enable inputs are “open”.

If the user desires to begin operation of the internal combustionengine, which is indicated by movement of the ignition switch, thecontrol unit causes the shutdown switching element 54 to transition intothe open condition. In this condition, the ignition circuit 48 isdisconnected from the ground 56. At the same time, both the starterswitching element 66 and the auxiliary switching element 72 transitionto the closed condition such that the battery cells 34 are connected toboth the auxiliary loads 76 and the starter motor 64, as shown in FIG.11C. At this time, the first enable signal goes to the high, 12 V level.

Once the internal combustion engine begins running, which the controlunit senses through the RPM input pin, the control unit causes thestarter switching element 66 to transition into the open condition,thereby disconnecting the battery cells 34 from the starter motor 64,while maintaining the auxiliary switching element in a closed condition,as shown in FIG. 11B. At this time, the first enable signal is highwhile the second enable signal is an open circuit since the engine isrunning. As can be understood in FIGS. 11A-11C, the control unitcontained within the battery pack 40 can start the internal combustionengine, control the battery power connections to the auxiliary loads andterminate operation of the internal combustion engine.

In an embodiment that includes a key switch to start the internalcombustion engine, there will be two distinct enables. A first enablewill be for the auxiliary power on and the second will be for turning onthe starter motor. In a system including a push button in place of thekey switch, there could be one or two enables. With two enables, one ofthe enables would direct the push button signal to the control unit andthe other would send the state of the safeties (blades on/off and brakeon/off).

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope of the inventionis defined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral languages of the claims.

We claim:
 1. A battery pack for use in powering a starter motor to startan internal combustion engine and supplying power to one or moreauxiliary loads, the battery pack comprising: an outer housing; aplurality of battery cells enclosed in the outer housing; a starterswitching element positioned within the outer housing and locatedbetween the plurality of battery cells and the starter motor; anauxiliary switching element positioned within the outer housing andlocated between the plurality of battery cells and the auxiliary loads;and a control unit positioned within the outer housing and configured tocontrol a condition of the starter switching element and the auxiliaryswitching element to selectively couple the plurality of battery cellsto the starter motor and the auxiliary loads.
 2. The battery pack ofclaim 1 further comprising an ignition input terminal configured to beconnected to an ignition circuit of the internal combustion engine,wherein the control unit includes an RPM input pin connected to theignition input terminal.
 3. The battery pack of claim 2 wherein thecontrol unit determines an operational status of the internal combustionengine based upon a signal on the RPM input pin.
 4. The battery pack ofclaim 1 further comprising a shutdown switching element positionedbetween the ignition input terminal and a ground, wherein the controlunit is configured to control a condition of the shutdown switchingelement.
 5. The battery pack of claim 4 wherein the shutdown switchingelement is transitioned to a first state to connect the ignition inputterminal to ground to either terminate operation of the internalcombustion engine or to prevent cranking of the internal combustionengine.
 6. The battery pack of claim 1 further comprising an enableterminal that is configured to be connected to an ignition switch of theinternal combustion engine.
 7. The battery pack of claim 6 wherein theignition switch is a push button.
 8. The battery pack of claim 6 whereinthe ignition switch is a multi-position key switch.
 9. The battery packof claim 6 further comprising a second enable input pin that isconnected to an axillary bus connected to an axillary terminal of thebattery pack.
 10. A battery pack for use in powering a starter motor tostart an internal combustion engine and supplying power to one or moreauxiliary loads, the battery pack comprising: an outer housing; aplurality of battery cells enclosed in the outer housing; a starterterminal; a starter switching element positioned within the outerhousing and located between the plurality of battery cells and thestarter terminal; an auxiliary terminal; an auxiliary switching elementpositioned within the outer housing and located between the plurality ofbattery cells and the auxiliary terminal; at least one enable terminal;an ignition input terminal; a shutdown switching element positionedbetween the ignition input terminal and a ground; and a control unitpositioned within the outer housing and configured to control acondition of the starter switching element, the auxiliary switchingelement and the shutdown switching element to selectively couple theplurality of battery cells to the starter motor and the auxiliary loadsand to enable operation of the internal combustion engine.
 11. Thebattery pack of claim 10 further comprising a second enable terminal.